title: Antiferro-quadrupolar structures in UPd3 inferred from x-ray resonant Bragg diffraction.
abstract: A systematic analysis of resonant x-ray Bragg diffraction data for UPd(3), with signal enhancement at the U M(IV) edge, including possible structural phase transitions leads to a new determination of the space groups of the material in the phases between T(0)=7.8 K and T(+1)=6.9 K, as P 222(1), and between T(-1)=6.7 K and T(2)=4.4 K, as P2(1). In addition, the quadrupolar order parameters, {Q(ab)}, inferred from diffraction data for the phase between T(-1) and T(2), are {Q(xz)} and {Q(yz)} at the (103) Bragg reflection and {Q(xy)} at the (104) reflection.
authors.affiliation: European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex, France.
authors.forename: Javier
authors.initials: J
authors.lastname: Fernández-Rodríguez
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Lovesey
authors.forename: Jesús A
authors.initials: JA
authors.lastname: Blanco